A Cutting Assembly

The present disclosure relates to a cutting assembly for a hair cutting device and the hair cutting device.

Hair cutting devices typically including a guard blade and a cutting blade which must be perfectly aligned for the best hair cutting performance. Tolerances in manufacturing and in manual replacement of cutting blades, however, can result in misalignment of the cutting blade with the guard blade.

According to a first specific aspect, there is provided a cutting assembly for a hair cutting device, the cutting assembly comprising:

It may be that the input device of the adjustment mechanism comprises an elongate rod extending along a rod axis, and a wheel at an axial end of the rod. It may be that the input device is configured to be moveable along the rod axis relative to the y-gear mechanism to engage and disengage the y-gear mechanism to thereby switch the adjustment mechanism between the y-set configuration and the neutral configuration, respectively.

It may be that the y-gear mechanism comprises a first worm gear and a second worm gear, which are spaced apart along a direction parallel to the x-axis and secured by a base, wherein the base is coupled to the cutting blade. It may be that the first worm gear and the second worm gear comprise respectively a first helical worm meshed with a first worm wheel and a second helical worm meshed with a second worm wheel, such that, when simultaneously engaged by the input device in the y-set configuration, the first worm gear and the second worm gear are configured to move the cutting blade along the y-axis relative to the guard blade.

Having two worm gears spaced apart along a direction parallel to the x-axis and simultaneously engaging them in the y-set configuration means that two sides of the cutting blade can be simultaneously moved, to reduce the likelihood of accidental angular movement of the cutting blade relative to the guard blade without requiring a guide.

It may be that the rod comprises a first y-key and a second y-key, spaced apart along the rod axis by the same amount as the first worm gear and the second worm gear. It may be that the rod passes through the first helical worm and the second helical worm. It may be that in the y-set configuration, the first y-key is configured to engage with the first helical worm, and the second y-key is configured to engage with the second helical worm so that rotation of the wheel of the input device forces rotation of the first helical worm and the second helical worm, which forces corresponding rotation of the first and second worm wheel, thereby moving the cutting blade along the y-axis relative to the guard blade. It may be that in the neutral configuration, the first y-key and the second y-key are configured to disengage from the first and second helical worms so that rotation of the wheel of the input device does not move the cutting blade relative to the guard blade.

It may be that the guard blade comprises a plurality of rod holders comprising an aperture through which the rod is passed and through which the rod is moveable along the rod axis, rod axis wherein the apertures in the rod holders are elliptical to permit movement of the rod along the y-axis.

It may be that a biasing element is disposed between the guard blade and the base, which is configured to bias the base from the guard blade so that the cutting axis is biased away from the x-axis in a direction towards the guard blade, so that the cutting teeth do not protrude beyond the guard teeth. This is important to ensure safety of the mechanism. The teeth on the cutting blade are typically much sharper than those of the guard blade, and so biasing the cutting blade to prevent protrusion of the cutting teeth improves safety for a user.

It may be that the first worm wheel and the second worm wheel comprise an eccentric protrusion which is configured to engage a respective buttress on the guard blade to apply a force to the guard blade from the base opposing the force applied to the guard plate by the biasing element, to enable fine tuning of the position of the cutting axis along the y-axis relative to the guard blade by manipulating the input device.

It may be that the adjustment mechanism is further configured to be switched to an x-set configuration, wherein in the x-set configuration, the input device is disengaged from the y-gear mechanism and engaged with an x-gear mechanism which is configured to move the cutting blade along the cutting axis, such that manipulation of the input device forces movement of the x-gear mechanism which moves the cutting blade along the cutting axis relative to the guard blade.

The input device may be configured so that movement along the rod axis of the input device switches the adjustment mechanism between the y-set configuration, the x-set configuration, and the neutral configuration.

It may be that the x-gear mechanism comprises a third helical worm disposed between the first worm gear and the second worm gear, and configured to engage with a base gear of the base, such that the cutting blade is moved along the cutting axis relative to the guard blade when the third helical worm is turned by the input device.

It may be that the base gear comprises an internal thread on the base, corresponding to an external thread of the third helical worm.

It may be that the rod comprises an x-key, disposed between the first y-key and the second y-key. It may be that in the y-set configuration, the x-key is configured to disengage from the third helical worm, so that manipulation of the input device does not move the cutting blade along the cutting axis. It may be that in the x-set configuration, the x-key is configured to engage with the third helical worm, the first y-key is configured to disengage with the first helical worm of the first worm gear, and the second y-key is configured to disengage with the second helical worm of the second worm gear so that manipulation of input device forces rotation of the third helical worm, thereby moving the cutting blade along the cutting axis relative to the guard blade, and not moving the cutting blade along the y-axis relative to the guard blade. It may be that in the neutral configuration, the x-key is configured to disengage from the third helical worm so that manipulation of the input device does not move the cutting blade relative to the guard blade.

It may be that the adjustment mechanism is further configured to be switched to an angular-set configuration, wherein in the angular-set configuration, the input device is disengaged from the y-gear mechanism and engaged with an angular-gear mechanism, such that manipulation of the input device forces movement of the angular-gear mechanism which moves the cutting blade to rotate about an angular axis perpendicular to both the cutting axis and the y-axis.

It may be that the angular gear mechanism comprises a part of the y-gear mechanism.

The input device may be configured so that movement along the rod axis of the input device switches the adjustment mechanism between the y-set configuration, the angular-set configuration, and the neutral configuration. The input device may be configured so that movement along the rod axis of the input device switches the adjustment mechanism between the y-set configuration, the angular-set configuration, the x-set configuration and the neutral configuration.

It may be that the angular-gear mechanism comprises the first worm gear or the second worm gear.

It may be that in the angular-set configuration, an angular-key is configured to engage the first helical worm or the second helical worm, the first y-key is configured to disengage from the first helical worm, the second y-key is configured to disengaged from the second helical worm, and the x-key is configured to disengage from the third helical worm, so that manipulation of the input device causes angular rotation of the cutting blade relative to the guard blade, and does not move the cutting blade along the cutting axis or along the y-axis relative to the guard blade.

According to as second aspect, there is provided a hair cutting device comprising a handle; a cutting assembly according to the first aspect; and a driving mechanism configured to reciprocally move the cutting blade along the cutting axis relative to the guard blade.

These and other aspects will be apparent from and elucidated with reference to the embodiments described hereinafter.

shows a hair cutting devicecomprising a handleand a cutting assemblywhich is configured to cut hairs.

respectively show an assembled view and an exploded view of the cutting assembly.

The cutting assemblycomprises a guard blade, a cutting bladeand an adjustment mechanism.

The cutting bladeis configured to cooperate with the guard bladeto cut hairs. Specifically, the guard bladecomprises a plurality of guard teethdistributed along a top edge of the guard blade. The guard bladedefines an x-axiswhich passes through tips of the guard teeth. The cutting bladecomprises a plurality of cutting teethextending along a cutting edge of the cutting blade, and defining a cutting axiswhich passes through tips of the cutting teeth.

The guard bladeand the cutting bladeare substantially planar and the guard bladeis assembled adjacent to the cutting bladeso that the cutting teethoverlap with the guard teeth, and so that the guard bladeand the cutting blade are configured to slide within a blade plane, which is parallel to the plane of each of the guard bladeand the cutting blade, relative to one another. While sliding within the blade plane, the guard bladeand the cutting bladeare configured to remain in contact, and in this example, the cutting axisis shown to be collinear with the x-axisin. In some examples, the cutting axismay not be collinear with the x-axis, but may be configured to be parallel to the x-axis. In other examples, the cutting axismay not be parallel to the x-axis, but is configured to parallel to the x-axisfor best alignment in use. The adjustment mechanism may therefore be configured to correct an alignment of the cutting axisso that it is parallel to the x-axis.

In use, the cutting bladeis configured to move reciprocally along the cutting axisrelative to the guard blade, such that the cutting teethand the guard teethcooperate to cut hairs. Referring back to, the hair cutting devicecomprises a driving mechanismwhich is configured to reciprocally move the cutting bladealong the cutting axisrelative to the guard blade.

Referring back to, in this example, the cutting assemblycomprises a basewhich is coupled to the cutting bladeand constrained on the guard blade.

The baseis constrained along the x-axisrelative to the guard bladeby a pair of buttressesprotruding from the guard blade, each buttresshaving an overhang. Sides of the baseare slotted under the overhang of the buttressesto constrain relative movement of the guard bladeand the basein a direction perpendicular to the blade plane. The sides of the basealso abut the respective buttressesso that the buttressesprevent relative movement of the baseand the guard bladein a direction parallel to the x-axis. The baseis moveable along a y-axisrelative to the guard blade, where the y-axisis perpendicular to the x-axis, and parallel to the blade plane. The baseis biased along the y-axisrelative to the guard bladeby a biasing clementin the form of a pair of compression springswhich respectively act between a pair of stopsof the guard bladeand the baseto bias the baseaway from the guard teeth. A counteracting force along the y-axis, to the force applied by the biasing element, is provided by the baseabutting the buttresses, which will be described in more detail below, to provide adjustment of the basealong the y-axisrelative to the guard blade.

The cutting bladeis configured to move reciprocally along the cutting axisrelative to the base. In this example, the cutting bladeis constrained to move only along the cutting axisrelative to the base, such that it does not move along the y-axisrelative to the base. Therefore, when the baseis moved along the y-axisrelative to the guard blade, the cutting bladeis also moved along the y-axisrelative to the guard bladeby a corresponding amount. The cutting bladeis constrained so that it cannot move relative to the basealong the y-axisby abutting the baseand being held in place by a double-sided torsional spring element.

Therefore, biasing the basewith the biasing clementtowards a bottom edge of the guard blade(opposing the top edge of the guard bladewhere the guard teethare distributed) also biases the cutting bladetowards the bottom edge of the guard blade. This biases the cutting axisaway from the x-axisin a direction towards the bottom edge of the guard blade, so that the cutting teethdo not protrude beyond the guard teeth. Biasing the cutting bladein this direction is an important safety feature of the cutting assembly. The cutting teethare typically much sharper than the guard teeth, and so biasing the cutting bladeto prevent protrusion of the cutting teethimproves safety for a user.

The double-sided torsional spring elementis coupled between the baseand two points on the cutting bladespaced along a direction parallel to the cutting axis. The torsional spring clementsimultaneously prevents the cutting bladefrom moving away from the basealong the y-axis, biases the cutting bladeagainst the guard bladeperpendicular to the blade plane to ensure that the guard bladeand the cutting bladeremain in contact, and biases the cutting bladetowards a central position along the cutting axisrelative to the base.

The adjustment mechanismcomprises an input device which is configured to be manipulated by the user in order to adjust the cutting assembly. In this example, the input device comprises an elongate rodextending along a rod axisand a wheelat an axial end of the rod. In this example, the rodcomprises a plurality of keys(best seen in) spaced apart along the rod. The keysare specially shaped protrusions from the rodwhich cooperate with corresponding key slot in gear sets to engage respective gear sets. In this example, the rod axisis parallel to the x-axisand the cutting axis.

The adjustment mechanismin this example is configured to be switched between a y-set configuration, an angular-set configuration, an x-set configuration and a neutral configuration which will be described in more detail below with reference to. In some examples, the adjustment mechanism may be configured to switch between only the y-set configuration and the neutral configuration. In some examples, the adjustment mechanism may be configured to switch between only the y-set configuration, the x-set configuration, and the neutral configuration. In other examples, the adjustment mechanism may be configured to switch between only the y-set configuration, the angular configuration and the neutral configuration.

In this example, the adjustment mechanismis configured to switch between the configurations by moving the input device along the rod axis.

In this example, the adjustment mechanismcomprises a first worm gearand a second worm gearwhich are spaced apart along a direction parallel to the rod axis. The first worm gearcomprises a first helical wormand a first worm wheelwhich are meshed together. The second worm gearcomprises a second helical wormand a second worm wheelwhich are meshed together (best seen in). The rodpasses through the first helical wormand the second helical wormso that the first helical wormand the second helical wormare spaced apart along the rod axis.

In this example, the first worm wheeland the second worm wheelare secured to the baseon opposing sides of the base, so that they rotate about an axis perpendicular to both the x-axisand the y-axis. The first worm wheeland the second worm wheeleach comprise eccentric protrusionswhich are configured to engage respective buttressesprotruding from the guard bladeto provide a force to the basealong the y-axiscounteracting the force applied by the compression springsto the base. Rotation of the first worm wheeland the second worm wheelin the same direction therefore either pushes the buttressesof the guard bladeaway from the cutting edge of the cutting bladeor allows the buttressesto come closer to the cutting edge of the cutting bladeunder action of the compression springs, so that the cutting axisis controllably moved along the y-axis.

In this example, the first worm gearand the second worm geartherefore together form a y-gear mechanism which, when engaged respectively by a first y-keyand a second y-keyof the input device (i.e., the rod), best seen in, enables the cutting bladeto be moved along the y-axis relative to the guard bladeto fine tune alignment of the cutting axiswith the x-axis, upon manipulation of the input device. This will be explained in more detail below with reference to.

In this example, the guard bladecomprises a plurality of guard rod holders(best seen in) and the basecomprises a plurality of base rod holders. Each of the rod holders,comprises an aperture through which the rodis passed and through which the rodis moveable along the rod axis. In this example, the first helical wormis disposed between a pair of base rod holdersand the second helical wormis disposed between another pair of base rod holders, spaced apart along a direction parallel to the x-axis, to secure each helical wormin place along the rod axis. The apertures in the guard rod holdersare elliptical, with the longer dimension parallel to the y-axis, to permit movement of the rodalong the y-axisrelative to the guard blade.

In this example, the first worm gearby itself (without the second worm gear) forms an angular-gear mechanism which, when engaged by a keyof the input device, enables the cutting bladeto be rotated relative to the guard bladeabout an angular axis, which is perpendicular to both the x-axisand the y-axis, upon manipulation of the input device. This will be explained in more detail with reference to. In other examples, the second worm gearby itself may form the angular-gear mechanism. Therefore, the angular-gear mechanism may comprise a part of the y-gear mechanism. In other examples, there may be a completely separate gear mechanism which is used to adjust the angle of the cutting bladerelative to the guard blade. In further examples, there may be no angular-gear mechanism.

In this example, the adjustment mechanismcomprises a third helical wormwhich, in this example, is disposed between the first helical wormand the second helical wormThe rod) also passes through the third helical worm. The third helical wormis configured to engage with a base gear of the basewhich in this example is an internal thread (not shown) on the basewhich meshes with an external thread on the third helical wormso that rotation of the third helical wormresults in movement of the cutting bladealong the cutting axisrelative to the guard blade. In other examples, the third helical worm may engage with a rack on the base extending parallel to the x-axisto enable movement of the cutting blade along the cutting axis(parallel to the x-axis) relative to the guard blade. In this example, the third helical wormand the base gear form an x-gear mechanism which, when engaged by an x-keyof the input device (i.e., the rod)), enables the cutting bladeto be moved along the x-axis relative to the guard blade, upon manipulation of the input device. This will be explained in more detail below with reference to.

shows the cutting assembly in the neutral configuration. In the neutral configuration the input device is disengaged from the y-gear mechanism, the angular gear mechanism and the x-gear mechanism, so that the input device can be manipulated freely (i.e., the wheelcan be rotated freely) without resulting in movement of the cutting bladerelative to the guard bladealong the y-axis), or the cutting axis, or any movement by angular rotation.

The first helical wormthe second helical wormand the third helical wormare all locked in place by friction between the components which is increased by the biasing elementpushing the components together.

shows the cutting assemblyin the y-set configuration in which the wheelis pulled away from the guard bladeand the cutting bladealong the rod axisto switch the adjustment mechanismfrom the neutral configuration to the y-set configuration, so that the adjustment mechanismis engaged with the y-gear mechanism. In this example, the y-gear mechanism is engaged by the first y-keyengaging a first key slotin the first helical wormand the second y-keyengaging a second key slotin the second helical wormThe keysmay be rectangular protrusions from the rod) which interlock with corresponding rectangular slots in the helical worms. In other examples, the keysand corresponding interlocking slots may comprise a many-sided cross-section, for example a hexagonal cross-section or a cross-section having more than 6 sides, such as 10 sides. Alternatively, the cross-section may be an angularly repeated cross-section, such as a spike which is repeated angularly many times to form a star shape. The more repeated angular sections the cross-section has, the more likely that rotation of the rodabout the rod axiswill allow the rodto be moved along the rod axisto interlock with a corresponding slot.

The first y-keyand the second y-keyare spaced apart along the rod axisby the same amount as the first worm gearand the second worm gear(or by the same amount as the first helical wormand the second helical worm) so that the first worm gearand the second worm gearcan be simultaneously engaged and disengaged by moving the input device along the rod axisrelative to the base, thereby moving the first y-keyand the second y-keyrelative to the first worm gearand the second worm gear.

In the y-set configuration, rotation of the wheelof the input device forces rotation of the first helical wormand the second helical wormwhich forces corresponding rotation of the first worm wheeland second worm wheelthereby moving the cutting bladealong the y-axisrelative to the guard blade.

The y-gear mechanism is disengaged by all keys-disengaging from either one or both of the first key slotor the second key slotas is shown in, so that rotation of the wheeldoes not move the cutting bladerelative to the guard bladealong the y-axis.

Having two worm gears spaced apart along a direction parallel to the x-axisand simultaneously engaging them in the y-set configuration means that two sides of the cutting bladecan be simultaneously moved, to reduce the likelihood of accidental angular movement of the cutting bladerelative to the guard bladewithout requiring a guide.

shows the cutting assemblyin the x-set configuration in which the wheelis pulled out, away from the guard bladeand the cutting blade, along the rod axisfurther from the y-set configuration so that the adjustment mechanismis disengaged from the y-gear mechanism and so that the adjustment mechanismis engaged with the x-gear mechanism. In this example, the x-gear mechanism is engaged by the x-keyengaging a third key slotin the third helical worm. The x-keyis disposed between the first y-keyand the second y-key